Optimistic concurrency control in DBMS Theory - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to describe the main idea of optimistic concurrency control.

DBMS Theory

In optimistic concurrency control, transactions proceed without locking and conflicts are checked at [1].

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Acommit time

Bstart time

Cread time

Drollback time

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing commit time with start time for conflict checking.

Thinking conflicts are checked during reading data.

Optimistic concurrency control allows transactions to run without locks and checks for conflicts only when the transaction tries to commit.

2fill in blank

medium

Complete the sentence about the main phases of optimistic concurrency control.

DBMS Theory

The three phases are read, [1], and validation.

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Awrite

Block

Crollback

Dcommit

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing write phase with locking phase.

Thinking rollback is a main phase.

Optimistic concurrency control has three phases: read, write, and validation.

3fill in blank

hard

Fix the error in the statement about conflict detection in optimistic concurrency control.

DBMS Theory

Conflicts are detected during the [1] phase, which ensures no overlapping writes.

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Aread

Bvalidation

Cwrite

Dcommit

Attempts:

3 left

💡 Hint

Common Mistakes

Thinking conflicts are detected during the read phase.

Confusing commit phase with validation.

Conflicts are detected during the validation phase to ensure no conflicting writes occurred.

4fill in blank

hard

Fill both blanks to complete the description of optimistic concurrency control phases.

DBMS Theory

Transactions first [1] data without locking, then [2] changes before validation.

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Aread

Block

Cwrite

Dcommit

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up locking with reading phase.

Confusing commit with writing phase.

Transactions read data without locking and then write changes before validation.

5fill in blank

hard

Fill all three blanks to complete the optimistic concurrency control validation step.

DBMS Theory

During validation, the system checks if any transaction [1] the same data, if so, the current transaction [2] and must [3].

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Aread

Bwrite

Caborts

Dcommits

Attempts:

3 left

💡 Hint

Common Mistakes

Thinking validation checks reads instead of writes.

Confusing commit with abort in case of conflict.

Validation checks if any transaction wrote the same data. If yes, the current transaction aborts and must read again.